Introduction: Lack of resources and efficient use of the available resources are among the challenges facing hospital management. Length of stay is one of the fundamental components of hospital performance. The aim of this study was to determine the relationship between the levels of care for patients and length of stay in hospital. Materials and Methods: This was a cross-sectional descriptive study. Scientific information using related library resources, online articles and dissertations was collected and data related to variables, average stay, and need for patient care using nursing report forms and patient cases have been collected from 204 cases in Hazrat Rasool Complex, Tehran, Iran in 2013. Results: There are significant differences between the average stay in different departments. The level of care needed with an average length of stay had strong and significant correlation. Gender, age, and marital status have no significant effect on the average length of stay. Conclusion: Although the overall performance of the hospital due to the need for patient care was desirable and appropriate, a great improvement can be achieved by enhancement of the levels of patient care.